A coating composition of a copolymer of methyl methacrylate with the polymerizable addition reaction product of an alpha,beta-ethylenically unsaturated acid and an epoxy compound

ABSTRACT

A liquid coating composition is formed by copolymerizing without gelation, 50-95 parts by weight of a methyl methacrylate lacquergiving monomer component and 5-50 parts by weight of a polymerizable addition reaction product obtained by the addition reaction of an Alpha , Beta -ethylenically unsaturated acid and an epoxy compound. In those instances where a polyepoxy compound (e.g., diepoxide) is used, the addition reaction is controlled to the extent that a sufficient amount of monoester and an insufficient amount of diester are formed so that substantially no gelatin occurs during copolymerization and/or formation of the coating composition. Films are formed from the coating composition which exhibit excellent durability, impact resistance, shrink resistance, and gasoline resistance.

United States Patent Nagata et al.

[451 Oct. 10, 1972 154] A COATING COMPOSITION OF A COPOLYMER OF METHYLMETHACRYLATE WITH THE POLYMERIZABLE ADDITION REACTION PRODUCT OF ANa,,B- ETHYLENICALLY UNSATURATED ACID AND AN EPOXY COMPOUND [72]Inventors: Nobuyoshi Nagata, 177 Gakuen- Daiwacho-4-chome, Nara-shi;Ryuzo Mizuguchi, 1736 Mashita- Shimokama Mishimacho, Osaka, both ofJapan [22] Filed: Dec. 18, 1969 [21] Appl. No.: 886,419

Related US. Application Data [63] Continuation-in-part of Ser. No.653,321, July 14, 1967, abandoned.

[52] US. Cl. ..260/836, 260/17, 260/30.6, 260/3l.8 M, 260/41 R,260/80.8, 260/837,

[51] Int. Cl. ..C09d 3/80 [58] Field of Search ..260/836, 837

I561 e aensac d UNITED STATES PATENTS 3,301,743 l/1967 Fekete et al...........260/837 X 3,373,075 3/ 1968 Fekete et al. ..260/837 X3,507,821 4/1970 Vasta ..260/836 X 3,524,902 8/1970 Feltzin et a1...260/836 X Primary Examiner--Wi1liam H. Short Assistant Examiner-L. M.Phynes Attorney-Beveridge & De Grandi [57] ABSTRACT A liquid coatingcomposition is formed by copolymerizing without gelation, 50-95 parts byweight of a methyl methacrylate lacquer-giving monomer component and5-50 parts by weight of a polymerizable addition reaction productobtained by the addition reaction of an a,B-ethylenically unsaturatedacid and an epoxy compound. In those instances where a polyepoxycompound (e.g., diepoxide) is used, the addition reaction is controlledto the extent that a sufficient amount of monoester and an insufficientamount of diester are formed so that substantially no gelatin occursduring copolymerization and/or formation of the coating composition.Films are formed from the coating composition which exhibit excellentdurability, impact resistance, shrink resistance, and gasolineresistance.

7 Claims, No Drawings COATING COMPOSITION OF A COPOLYMER OF METHYLMETHACRYLATE WITH THE POLYMERIZABLE ADDITION REACTION PRODUCT OF ANa,B-ETHYLENICALLY UNSATURATED ACID AND AN EPOXY COMPOUND CROSS-REFERENCEThis application is a continuation-in-part of our copending applicationSer. No. 653,321 filed July 14,

1967, now abandoned.

This invention relates to coating compositions and films formedtherefrom. Most particularly, this invention relates to improved methylmethacrylate lacquers which form films of exceedingly high quality.

Generally, films formed from a lacquer containing methyl methacrylatepolymer as a main film-forming component exhibit, to a high degree, thedesirable properties of being color-free and transparent, as well ashaving good gloss retention and resistance to yellowing. Unfortunately,such films tend to suffer not only from the problem of cracking whenthey are subjected to expansion and contraction caused by temperaturevariations, but also from the problem of swelling and shrinking whencontacted by moisture. Furthermore, these films are often undesirablylow in impact resistance and exhibit poor adhesive characteristics. Theproblems of shrinking and cracking are particularly prevalent when thelacquers are applied to other films or are applied as a recoat uponthemselves.

In order to overcome such drawbacks as cracking and inferior capabilityof being recoated, the art has produced methyl methacrylate lacquers bycopolymerizing methyl methacrylate with about 2-30 percent by weight ofanother monomer as an intraplasticizing monomer, particularly anacrylate or methacrylate of an alkanol having two to 22 carbon atoms.However, when a methyl methacrylate lacquer film has been so improved toprevent cracking or to improve its capability of being recoated, thefilm is generally low in gasoline resistance. This is ascribable to thefact that the intraplasticizing .monomer employed is highly compatiblewith gasoline. Thus, the

' greatest problem of the conventional methyl methacrylate lacquerscomprising a polymer composed mainly of a methyl methacrylate monomer isthat the art has not been able to obtain a copolymer composition whichproperly balances, at sufficiently high levels, the important propertiesof crack resistance, shrink resistance, recoatability, and gasolineresistance.

The present invention overcomes the abovedescribed problem by providinga coating composition comprising an organic solvent soluble copolymerob- 3 tained bythe copolymerization reaction of (a) 50-95 parts byweight and preferably 55-95 parts by weight of a methyl methacrylatelacquer-giving component, and (b) 5-50 parts by weight and preferably5-45 parts by weight of a polymerizable addition reaction product of ana, B-ethylenically unsaturated acid and epoxy compound in an amount ofabout 0.l l0.0 times the number of moles of acid employed. The films orcoatings formed from such a coating composition comprise a polymer whichhas a hydroxyl group and an epoxy component in its molecule and which,after solvent evaporation, exhibits a superior and excellent balancebetween crack resistance, shrink resistance,

recoatability, and gasoline resistance. In addition, the films haveexcellent hardness, impact resistance and flexibility, as well asexhibiting The qualities of colorlessness, transparency, gloss retentionand yellow resistance, normally associated with methyl methacrylates.

The term methyl methacrylate lacquer-giving compound is well understoodin the art and is used herein in accordance with its well known meaning.Generally speaking, methyl methacrylate lacquer-giving compounds arethose compounds composed of methyl methacrylate either alone or inadmixture with copolymerizable monomers in an amount insufficient todestroy the methyl methacrylate properties of the lacquer. Generallyspeaking, the monomer(s) copolymerizable with the methyl methacrylateshould not exceed about 2-30 percent by weight of the methylmethacrylate since at percentages greater than about 30 percent byweight the lacquer starts to lose those properties and characteristicsassociated with methyl methacrylate.

The above-mentioned copolymerization of the methyl methacrylatelacquer-giving polymerizable monomer with the said addition reactionproduct may generally be effected by heating an admixture of these twoingredients at a temperature of C to l60 C in the presence of apolymerization initiator as will be illustrated more fully hereinafter.For the purposes of this invention it is important that the copolymerformed be solvent soluble so that substantially no gelation occurs inthe coating composition or during copolymerization. Thus, the copolymerformed should not be convertible during copolymerization into across-linked insoluble copolymer or a copolymer which is insolublebecause of its very high molecular weight.

By the term solvent soluble is meant a copolymer which is soluble atoperating temperatures in conventional methyl methacrylate lacquersolvents.

When a monoepoxide compound is used to form the addition reactionproduct in accordance with this invention, a monoester is formed withthe a, B-ethylenically unsaturated acid. The copolymerization productformed from this monoester and the methyl methacrylate monomer isgenerally soluble under all operating and environmental conditions inthe conventional methyl methacrylate lacquer solvents. However, when adiepoxide or other polyepoxide compound is used, diesters tend to formduring the addition reaction, which diesters if present in sufficientamounts, will render the copolymer product insoluble at ambienttemperatures or under the temperatures of copolymerization, thus causingthe coating compositions either during copolymerization or upon storageto form undesirable, and often inoperable, insoluble gels.

It has been found, and with partial reference to the above, that thecompositions of the subject invention must have three basiccharacteristics in order to provide a solvent soluble (i.e.,non-gelling) composition which forms films having an excellent andsuperior balance between shrink resistance, recoatability, gasolineresistance, and crack resistance:

1. Firstly, the methyl methacrylate lacquer-giving monomer must be usedin an amount of at least about 50 percent by weight and preferably 55percent by weight or greater, so that the coating composition retainssufficient solubility characteristics and those desirable qualitiesnormally associated with methyl methacrylates;

2. Secondly, the amount of diester (e.g., divinyl monomer) formed duringthe addition reaction of the epoxide and a, B-ethylenically unsaturatedacid must be maintained below that amountwhich will cause gelation tooccur; and

3. Thirdly, as a general rule, at least 10 percent of the a,B-ethylenically unsaturated acid must be reacted with the epoxy compoundduring the addition reaction so that the necessary -50 parts by weightof the monoester: will be copolymerized with the methyl methacrylatelacquer-giving monomer without the expensive necessity of first havingto isolate the monoester from its addition reaction mass.

As can be seen, (2) and (3) above actually work in contradistinction toone another since the amount of diester increases as the amount of acidreacted during the addition reaction increases. Thus, (2) and (3) abovemust be carefully balanced if the unique results of this inventionare tobe economically and efficiently achieved.

There are several ways in which the amountof diester formed during theaddition reaction can be kept at a minimum. Firstly, one may use amonoepoxideor a mixture of monoand polyepoxides such that the amountofdiester formed is either zero or below the maximum that can betolerated. The use of monoepoxides is not always convenient or possiblesince, for example, in many instances polyepoxides are more availableand more economically used. In addition, it has been found desirable insome instances to have an unreacted epoxide group remain in the system.Thus, diepoxides, as the most preferred type of polyepoxides, are oftenmore desirable to use.

The addition reaction between a diepoxide and a, B- ethylenicallyunsaturated acid may be exemplified by the following formula:

l yields H O monoester) and Ilt R CHg=C-C0CHz-CHCH2- O AM CHr-CH-CHr- O-C :C Hz

(diester) The longer the addition reaction is allowed to proceed and themore acid that is allowed to react, the greater will be theamount ofdiester formed. Thus, the invention includes within its scope means bywhich the amount of diester formed may be controlled so that thecopolymerization step which follows the addition reaction will not forman insoluble gel.

Thefirst manner of controlling the diester is to include within theingredients of the addition reaction a chain transfer agent in an amountsufficient to maintain the amount of diester formed below that point atwhich gelation will occur during copolymerization. Although the amountof agent needed will differ as different systems are employed, it hasbeen found, for example, that when lauryl mercaptan is used as the chaintransfer agent, it should be used in an amount greater than 2.5 timesthe mole of the maximum amount of diester that can be tolerated.Examples of other chain transfer agents that can be used includen-butylmercaptan, ndodecylmercaptan, tert-butylmercaptan, ethylthioglycolate, benzenethiol and isopropylmercaptan.

It is not always desirable, economical, or possible to use a chaintransfer agent, for example, in those systems which cannot tolerate thepresence of such a chemical in the final product. For this reason, thisinvention also contemplates controlling the addition reaction throughits operating conditions in order to limit the amount of diester formedas more fully explained hereinafter.

The actual amount of monoester that must be present, and conversely theactual amount of diesters that can be tolerated in order to insureagainst gelation during polymerization will vary over a wide rangedepending upon the type polymers used, the type solvent employed, andthe like. Therefore,,each system will have its own tolerance limit.

In order to aid in ascertaining the tolerance limits for a given system,for example, when a diepoxide is used, the proportion of the monoesterof a diepoxide and the diester of a diepoxide produced when thediepoxide is reacted with an a, B-ethylenically unsaturated carboxylicacid can be calculated according to the following equation:

1. let the amount of diepoxide moles E,

2. let the proportion of the reacted diepoxide 1:.

At any value of x, the amount of diester produced i.e., the additionreaction product of one mole of diepoxide with two moles of carboxylicacid becomes [E,,]x moles. The amount of monoester produced then becomes2[E,,](l-x)x moles. Further, the amount of unreacted diepoxide becomes[E,]( l-x) moles.

The unknown amounts of diester and monoester can be calculated from theamount of the carboxylic acid consumed. That is, let the amount of thecarboxylic acid used equal [Ac] moles and let the proportion of thereacted carboxyl group equal y. At any given value of y, the amount ofthe carboxylic acid reacted becomes [Ac] y moles. Therefore:

[Epl/[AC] is a constant determined from the amount of the carboxylicacid used and the amount of the diepoxide used. The value of y" at anygiven time during reaction is easily determined by routine techniquessuch as titration or the like, to determine the amount of acid present,and thus the amount of acid reacted. Once y is determined, x is easilycalculated from which the amounts of monoester and diester can becalculated at any given time in the addition reaction. By

routine and conventional techniques then, the tolerance limits ofdiester for any particular system may be ascertained.

The following illustrates one set of experiments conducted wherein abifunctional epoxy resin was reacted with methacrylic acid using an[E,,]/[Ac] of 1:1 and 1:2, respectively. The acid reaction rate (y) wasdetermined by dividing the difference between the acid values before andafter reaction by the acid value before reaction.

By forming various admixtures of the above addition reaction productsand methyl methacrylate lacquergiving components and copolymerizingsame, the upper limit of diester tolerance for non-gelation duringcopolymerization for any given system may be ascertained.

Further examples of ascertaining y for other systems are shown in thefollowing table wherein the relationship between reaction time andamount of acid consumed are ascertained by using the same acid measuringtechnique as described hereinabove. Reaction 1 I consisted of reactingan equimolar ratio of Epikote 828 with methacrylic acid (i.e., [Ed/[Ac]1:1) in 30 percent xylene under reflux at 140 C. Reaction 2 was similarto Reaction 1 except the solvent was percent xylene and 10 percentcellosolve acetate under reflux at l50-l60 C. Reaction 3 was conductedby reacting Epikote 1001 with a double molar ratio of methacrylic acid(i.e., [Ed/[Ac] 1:2) in 30 percent xylene under reflux at 140 C. Thenumerical values presented are averages of a number of runs conducted.However, good reproducibility with relatively small differences were allthat occurred between the runs.

Similarly as stated above, once given y, the value of x at any giventime within the systems may be calculated. Further routinecopolymerization experimentation will then indicate at what point theaddition reaction should be terminated so as to provide an additionreaction product that will be sufficiently low in the di ester componentto prevent any substantial amount of" gelation from occurring duringcopolymerization and formation of a coating composition.

By the above routine experimentation, a control system based uponaddition reaction time and/or amount of acid consumed may be worked outfor any given polymeric system. Obviously, on a commercial basis whereone is producing a preferred commercial product, this routineexperimentation will comprise almost a negligible part of the start-uptime normally associated with such an operation. Thus a technique ishereby disclosed for controlling the amount of diester formed and thusinsuring against gelation upon copolymerization simply by measuringreaction time and without the need to use monoepoxides or chain transferagents.

For the purposes of this invention, any well known methyl methacrylatelacquer-giving component (sometimes referred to as monomer) may be used.This component or monomer may be comprised of methyl methacrylatemonomer alone or it may be comprised of an admixture of methylmethacrylate and a monomer copolymerizable therewith not exceeding about30 percent by weight of the methyl methacrylate and preferably fromabout 2-30 percent thereof.

Examples of monomers copolymerizable with methyl methacrylate which maybe used for the purposes of this invention include acrylates of analkanol having one to 18 carbon atoms, methacrylates of an alkanolhaving two to 18 carbon atoms, vinyl acetate, vinyl propionate, styrene,vinyl toluene, acrylonitrile, diesters of maleic or fumaric acid withalkanols having one to four carbon atoms, glycidyl acrylate, glycidylmethacrylate, acrylamide, methacrylamide, and derivatives thereof. Ofthese monomers, the first two named are most preferred.

Examples of a, B-ethylenically unsaturated acids useful in the additionreaction for the purposes of this invention include any of those wellknown materials such as acrylic, methacrylic, crotonic, itaconic, maleicand fumaric acids. Of these methacrylic acid is preferred.

Examples of monoepoxides which may be used in accordance with thisinvention include conventional and well known monoepoxides such asepichlorohydrin, glycidol, ethylglycidyl ether, butylglycidyl ether, 2-ethylhexylglycidyl ether, phenyl-glycidyl ether and Cardura E which is amonoepoxide produced by Shell Chemical Co. and represented by theformula:

wherein Risa C to C tertiary fatty acid residue.

Examples of polyepoxides, including diepoxides which may be used for thepurposes of this invention include those conventional polyepoxides wellknown in the industry such as for example, those polyepoxy compoundsobtained by the condensation reaction of bisphenol A withepichlorohydrins, and those polyepoxides represented by the formulas:

wherein n is -18, or

(2) CHzCHCHzOCHz-CH-+0 -CHz-CHOCHa-CH-CH2 O m I! 0 wherein m is about 3to about 5.6 and R and R" are acetate, butyl acetate, m ylhylk n organicradicals.

The compounds of formula (1) or (2) above may be I purchased under thefollowing trademarks:

Epikote 562, 815, 820, 828, 834, 871, 872, 1001, 1004, 1008,1009 and.1031 produced by Shell Chemical Co.,; Araldite 6071, 7071, 707 2, 7097,6097, 6099, CY 250, GY 225, GY 260 and GY 280 produced by Ciba Ltd., andDER" 330, 331, 332, 334, 335, 336, 337, 660, 661, 662,664, 667, 668,669, 732 and 736 produced by Dow Chemical Co.

Epikote 828 or 1001, for example, are represented by formula 1) abovewherein n is about 1 to about 2. DER 732, as another example, isrepresented by formula (2).above wherein m is about 5.

ln carrying out the above-described addition reaction, the a,B-ethylenically unsaturated acid is reacted with the epoxy compound at atemperature of 80 to 200 C in the presence of a radical polymerizationinhibitor such as hydroquinone or hydroquinone monomethyl ether whileone or more of the above diester controls is effected upon the systemuntil at least 10 percent of the acid is consumed.

In the present invention, unreacted carboxyl acid and unreacted epoxycompound may be left in the copolymer mass in various proportions byvarying the proportions of a,B-ethylenically unsaturated acid and epoxyresin within the ranges regulated in the invention and the extent of theaddition reaction thereof. The presence of each unreacted carboxyl groupand free epoxy compound has no substantial detrimental effect on thefilm-forming efficiency of the resulting coating composition since atleast 10 percent of the acid is cosumed and formed primarily into amonoester monomer. 0n the contrary, a suitable amount of the carboxylgroup present in the copolymer, when formed into a coating composition,materially aids wettability and miscibility with pigments, and the freeepoxy resin as well as unreacted epoxy groups serve as plasticizersinthe composition.

The copolymer of the present invention can be prepared according to anyof the known methods for polymerizing methyl methacrylate. Preferably,the polymerization is effected in a solution at 701 60 C in the presenceof a polymerization initiator such as a peroxide or azo compound. Duringpolymerization the viscosity of the solution in certain systems maybecome unreasonably high. In such instances, the viscosity may becontrolled by the use of any well known chain transfer agent such aslauryl mercaptan and the like.

As solvents for the preparation'of the copolymers and coatingcompositions of the present invention, there may be used solventsconventionally used for coating compositions, such as aliphatic,alicyclic and aromatic hydrocarbons, halogenated hydrocarbons, ethers,esters, ketones and alcohols. Of these, ethyl methylisobutylketone,toluene, xylene and ethylene glycol monoethyl ether acetate arefrequently used.

The coating compositions of this invention may also be used as so-calledcomposite lacquers by incorporation therein of a cellulose derivative.In such instances, the amount of cellulose derivative is preferably upto about 100 parts by weight per 100 parts by weight of the copolymer.1f the amount is more than said limit, the advantageous characteristicsof the copolymers of the present invention tend to be diminished orlost. Examples of such cellulose derivatives include nitrocellulose,cellulose acetate, cellulose propionate, cellulose acetate butyrate andthe like. Further, a solvent-soluble alkyd'resin or vinyl resin may alsobeadded in such an amount as not to substantially detract from theimproved characteristics of the copolymer as described above.

Many known plasticizers, which have heretofore been used in methylmethacrylate lacquers, may also be employed in the present compositions.These plasticizers include, for example, benzylbutyl phthalate, dibutylphthalate, triphenyl phosphate, 2-ethylhexylbenzyl phthalate anddicyclohexyl phthalate. These plasticizers may be used in proportions of5-30 parts by weight per 100 parts by weight of the copolymers.

In those instances where a transparent film is not necessary, thecoating compositions of the present invention may be colored by theaddition of pigments. Examples of pigments useful herein include oxides,hydroxides, silicates, chromates, sulfides, sulfates and carbonates ofmetals, various organic pigments, carbon blacks and metal flakepigments. These pigments may be used in conventional amounts. Further,surface active agents, such as agents that reduce flooding, floating orsilking which are ordinarily used in very slight amounts in preparingpaints, may also be added to the coating compositions of this invention.

The above-mentioned components which may be used in the coatingcompositions of this invention are insoluble therein according to knowntechniques for producing conventional methyl methacrylate lacquers.

The present coating compositions may be applied onto materials to becoated by any means such as flowing, dip coating, spray coating, brushcoating, roller coating and the like. However, the most preferablycoating means is spray coating.

The present coating compositions dry even at room temperature to givesufficiently hard films, but more preferable films can be obtained whenthe composi-- tions are forcibly dried at 200 C for 1-50 minutes.

The present coating compositions are excellent in adhesion andrecoatability and hence can be applied to many materials. Thecompositions are prominent also in weather resistance, so that they aremost effectively used as automotive finishing paints.

The present invention will be illustrated in further detail below withreference to examples, in which all the parts and percentages arebyweight unless otherwise indicated.

EXAMPLE l Butylglycidyl ether 103.00 pans Methacrylic acid 130.00 pansEthylene glycol monoethyl ether acetate 100.00 pans Hydroquinone 0.05pans The above materials were charged in a reactor, and the additionreaction of the epoxy group of butylglycidyl ether with the carboxylgroup of methacrylic acid was effected with stirring at l50-170 C for 7hours. This addition reaction may be effected in the presence of anamine catalyst such as triethylamine or may be effected merely at anelevated temperature as shown above. Since butylglycidyl ether used wasa monoepoxide, there was no fear that a diester would be formed.

From the above reaction mixture, ethyleneglycol monoethyl ether acetateand unreacted butylglycidyl ether and methacrylic acid were firstremoved by distillation at 50-54 C/3-l 5 mml-lg, and then the additionreaction product of methacrylic acid and butylglycidyl ether wasobtained at 105 C/2 mmHg. Although extraction was not absolutelynecessary, it was particularly preferred for the purposes of thisexperiment.

Methyl methacrylate 85.0 pans Addition reaction product obtained inl-(a) 15.0 parts Xylene 60.0 parts Toluene 45.0 parts The abovematerials were charged in a reactor provided with a stirrer and themixture'was heated to reflux. To the mixture maintained in a refluxstate, a solution of 1.0 part of azobisisobutyronitrile and 45.0 partsof ethyl acetate was added dropwise in a period of 2 hours to effect thepolymerization reaction. After the dropwise addition, the mixture washeated with reflux for an additional 2 hours. The resulting resinsolution had a non-volatile content of 40 percent and a viscosity of Kas measured by a Gardner-Holdt bubble viscometer.

EXAMPLE 2 Cardura E (as hereinbefore defined) 750.00 pans Methacrylicacid 301.00 pans Xylene 263.00 pans 0.15 parts l-lydroquinone monomethylether The above materials were charged in a reactor, and the mixture washeated to 140 C with stirring. The epoxy group of Cardura E" was strongin reactivity, and the reaction was completed in about 40 minutes togive an addition reaction product of Cardura E" and methacrylic acid.Since Cardura E is a monoepoxide, no fear of diester formation existed.The addition reaction product may be isolated as in the case of Examplel-(a), but the isolation thereof is not necessary, and

thus the addition product may be used as such in the form of a xylenesolution. In the subsequent reactions,

the addition product was used in the form of a xylene solution.

Addition product solution obtained in Example 2-'(b) 95.0 pans Methylmethacrylate 225.0 parts Xylene 181.0 pans Toluene 150.0 pans A mixtureof the above materials and a solution of 4.0 parts ofazobisisobutyronitrile and 100.0 parts of ethyl acetone were used toeffect polymerization in the same manner as in Example l-(b). Theresulting resin solution had a non-volatile content of 40 percent and aviscosity of V.

EXAMPLE 3 Addition product solution obtained in Example 2-(a) 94.0 pansMethyl methacrylate 175.0 pans Xylene 131.0 parts Toluene 112.5 parts Amixture of the above materials and a solution of 3.0 parts ofazobisisobutyronitrile and 112.5 parts of ethyl acetate were used toeffect polymerization in the same manner as in Example 1-(b). Theresulting resin solution had a non-volatile content of 40 percent and aviscosity of X.

EXAMPLE 4 Epikote 828 (as defined above) 700.00 pans Methacrylic acid172.00 pans Ethylene glycol monoethyl ether acetate 109.00 pans Xylene109.00 parts Hydroquinone monomethyl ether 0.09 parts Addition productsolution obtained in Example 4-(a) 133.0 parts Methyl methacrylate 270.0pans Lauryl mercaptan 3.0 pans Xylene 272.0 pans A mixtureof the abovematerials and a solution of 2.4 parts of azobisisobutyronitrile and 75.0parts of ethyl acetate were used to effect polymerization in the samemanner as in Example l-(b). The resulting resin was a solution withsubstantially no gelation and had a non-volatile content of 50 percentand a viscosity of 2,.

.1. EXAMPLE 5 Addition product solution obtained in Example Z-(a) 56.2parts Addition product solution obtained in Example 4-(a) 56.2 partsMethyl methacrylate 210.0 parts Lauryl mercaptan 2.0 parts Xylene 1 18.0parts Toluene:

A mixture of. the above materials and a solution of 3.0 partsv ofazobisisobutyronitrile and ethyl acetate were used to effectpolymerizationin the same manner as in Example l-(b). The resultingresin was a solution with nogelation and had a non-vo1atile content of50 percent and a viscosity of Z,

EXAMPLE 6 Addition product solution obtained in Example 2-(a) 100.0parts Methyl methacrylate 300.0 parts n-Butyl acrylate 20.0 parts Xylene220.0 parts Toluene 180.0 parts A mixture of the above materials and asolution of 5.0 parts of azobisisobutyronitrile and 180.0 parts of ethylacetate were used to effect polymerization in the same manner as inExample l-(b). The resulting resin solution had a non-volatile contentof 40 percent and a viscosity of U.

EXAMPLE 7 Addition product solution obtained in Example 4-(a) 125.0parts Methyl methacrylate 360.0 parts n-Butyl acrylate 40.0 parts Laurylmercaptan 2.6 pans Xylene. 375.0 parts A mixture of the above materialsand a solution of 4.0 parts azobisisobutyronitrile and 100.0 parts ofethyl acetate were used to efiect polymerization in the same manner asin Example I( b). The resulting resin solution had a non-vo1atilecontent of 50 percent and a viscosity of Z EXAMPLE 8 "Epi kote" 1001(diepoxide as defined above) 450.00 parts Methacrylic acid 86.00 partsEthylene glycol monoethyl ether acetate 136.00 parts Hydroquinone 0.03parts tofprevent any gelation. During this addition reaction theconsumption of acid was measured as described and the amounts of diesterand monoester calculated with the following resultsi Diester Methacrylicacid consumed Monoester 100.0 parts (Mole 9b (Mole qt (Mole a Furtherexperimentation revealed that not only is the 15 mole percent acidconsumption optimal, but that at percent acid consumption, thecopolymerization product formed therefrom is a totally solvent-insolublecopolymer not capable of being used in. a coating composition because itforms an insoluble gel in the solvent.

Addition product solution obtained i in Example S-(a) 100.0 parts Methylmethacrylate 344.0 parts Z-Ethylhexyl acrylate 38.4 parts Laurylmercaptan 2.0 parts Xylene 350.0 parts A mixture of the above materialsand a solution of 3.3 parts of azobisisobutyronitrile and 92.5 parts ofethyl acetate were used to effect polymerization in the same manner asin Example 1-(b). The resulting resin was a non-gelling solution and hada non-volatile content of 50 percent and a viscosity of 2;.

EXAMPLE 9 DER-" 732 (as defined above) 320.00 parts Methacrylic acid86.00 parts Xylene 101.00 parts l-lydroquinone 0.04 parts The abovematerials were charged in a reactor and the mixture was subjected toaddition reaction at -150 C. In a period of about 1 hour, 20 percent ofthe methacrylic acid was addition reacted. It is alsofound by routineexperimentation that at this time, temperature, andacidconsumptionlevel, the amount of diester formed is too little to cause any gelationduring copolymerization.

Addition product solution obtained in Example 9-(a) 75.0 parts Methylmethacrylste 216.0 pans n-Butyl acrylate 24.0 parts Lauryl mercaptan 1.5parts Xylene 105.0 parts Toluene 120.0 parts A mixture of the abovematerials and a solution of 3.0 parts of azobisisobutyronitrile and 60.0parts of ethyl acetate were used to effect polymerization in the samemanner as in Example l-(b). The resulting resin was a non-gellingsolution and had a non-volatile content of 50 percent and a viscosity of2,.

EXAMPLE 10 Addition product solution obtained in Example Z-(a) 56.2 pansAddition product solution obtained in Example 4-(a) 56.2 parts Methylmethacrylate 178.5 parts n-Butyl methacrylate 31.5 parts Laurylmercaptan 3.0 parts Xylene 109.5 parts Toluene 108.0 parts In forming atransparent film by use of the resin solution obtained in each of theabove examples, the resin solution may be charged with a dilutingsolventso as to have a viscosity suitable for coating and then appliedto a material to be coated. in case the solution is to be used as apigmented enamel, it is incorporated with pigments such as a leafingaluminum pigment, coloring matter and titanium oxide and, if necessary,a very slight amount of an agent that reduces flooding, floating orsilking, and is then subjected to such operation as mechanical impact,abrasion or stirring, whereby a smooth enamel is obtained. The thusobtained enamel may be charged with a diluting solvent so as to have aviscosity suitable for coating and then applied to a material to becoated.

Typical values of efficiencies of films formed from coating materialsusing the resins obtained in the above} examples are summarized in Tablel, in which Alpaste 1 109A (trade name for aluminum metal paste of ToyoAluminum K.l(.) was used as the leafing aluminum pig-I ment, Microlith4GT Blue (product of Ciba Ltd.) as; the coloring matter, and Rutile-typeTitanium Oxide R-8 20 (product of lshihara Sangyo KK.) as the titaniumoxide.

Tests on the efficiencies of films formed from the thus prepared coatingmaterials were effected in the following manners:

Each of the above coating compositions was sprayed onto a 0.8 mm thicksteel panel coated with an epoxy resin-modified acrylic type primer, andwas forcibly dried at 140 C for 30 minutes. Thereafter, the coatingcomposition was again applied onto the coated steel panel and was thenforcibly dried at 140 C for 30 minutes. The thickness of the film formedafter drying was controlled so that the thickness of the primer became40 p. and that of the present coating material became 40-50 1.. Thegloss of the sprayed film as such was evaluated by means of a glossmeter when the angle was 60. The hardness of the film was evaluatedaccording to pencil hardness and was represented by a maximum pencilhardness attained when the film was subjected to ordinary procedurewithout forming scratches. The impact strength was measured, by means ofa DuPont Impact tester, using a 500 g. weight of k inch diameter. Theadhesion was measured in such a manner that by means of a needle, onehundred squares of 2 X 2 mm were formed on the film, and an adhesivetape was applied onto the film and was then vigorously peeled off. If nosquares of the film had been peeled off, the adhesion of the film wasevaluated to be passed. The hot water resistance was tested by immersingthe film in city water at 40 C for 240 hours. The gasoline resistancewas evaluated by immersing the film in commercially available gasolineat room temperature for 24 hours and observing the appearance of theobtained film and measuring the pencil hardness thereof.

TABLE 1 Example No 1 2 a 4 s 1 Coating material composition:

Resin solution of example (a) (parts by weight) 250 250 250 175 250 175140 200 250 176 sec. NC solution (b) (parts by weight) 4 sec. CABsolution (c) (parts by weight)", 150 150 150 Rutile titanium oxide(parts by weight) 40 40 40 Leafing aluminum pigment (parts by weight) 44 4 4 4 4 4 F1 Coflgring matter (parts by weight) 3 3 3 3 3 3 3 1 In 8ClGl'lCleSZ 2;: s; 92 82 32. e a 2:2. e a s2. 22, a 2;; SSPeiieiiiigrrdness 2H 3H 2H 2H 2H H 3H 2H 2H 1 2H 2H 2H 2H Impactstrength (cm 25 25 30 20 26 25 d0 25 30 30 30 ldhelsiion test 13.80 1918518 ance:

. b e ti n assesses? 2H F B H H H 3H HE E HB F H 2H 211 Hot waterresistance 1 Excellent. 2 Passed. 3 Good.

Example No 8 9 50 NOTE: c g i material composia. Resin solutions ofExamples 1, 2, 3 and 6 have inifi, l z g z a r mg dividually anon-volatile content of percent,

8 a 1 S 1 ?vei g ht), Y 200 180 140 200 200 250 250 and those'ofExamples 9 and 0 ha e a ig*g, g gggg f olatlle content of 50 percent.V2(sec.tC11)&B solultitgn (c) 150 b. 4 sec. NC solution a solutioncomprising 20 8. S W01 a g g parts of ,5 sec. nitrocellulose, 16 partsof g g g r s g zfi gk methylethylketone and 64 parts ofmethylisobutylcnlient (part; by(weltght) 4 4 4 4 4 ketone 3 3 3 3 3 c. 4sec. CAB solution a solution comprising 20 Film efficieneies:

a ae 23 23 22 29 22 22 .4 fiffiffii fi i ii: i,f";- PM

oss a e 3 Pencil hardness. 2H 3H 3H 3H 3H 3H 3H y pa 0 me y my one,Impact strength (0 20 2o 30 30 25 25 20 12 parts of ethylene glycolmonoethyl ether gggggi gggig a) (2) (2) 2) (2) (2) (2) acetate, 8 partsof sec -butanol and 24 parts of c Appearance observat tion Hardnessretention... F H 3H 2H B B B 65 d. When polished, every film shows agloss of 94 or Hot water resistance... 0) 0) U) more.

Once given the. above disclosure, many other features, variations andmodifications will become apparent to those skilled in the art. Suchfeatures, variations and modifications are therefore considered withinthis invention, the scope of which is to be determined by the followingclaims.

We claim:

l. A'coating composition consisting essentially of an organic solventsoluble copolymer obtained from the copolymerizationreaction of (a)50-95 parts by weight of a member selected from. the group consistingof 1) methyl methacrylate and (2) an admixture of methyl methacrylateand 2'-30 percent by weight of a monomer" copolymerizable therewithselected from acrylates of an alkanol having one to 18 carbon atoms,methacrylates of an alkanol having two to 18 carbon atoms, vinylacetate, vinyl propionate, styrene, vinyl toluene, acrylonitrile,diesters of maleic acid with alkanols having one to four carbon atoms,diesters of fumaric acid with alkanols having one to four carbon atoms,glycidyl acrylate, glycidyl methacrylate, acrylamide and methacrylamide;and (b) 550 parts by weight of a polymerizable addition reaction productof an a,B-ethylenically unsaturated acid and a polyepoxy compound in anamount of about 0.li0.0 times the number of moles of said acid employed.

2. A coating composition in accordance with claim 1 wherein at leastpercent of the acid employed is allowed to react with said epoxycompound.

3. A coating composition in accordance with claim 1 wherein said epoxycompound is a polyepoxide and there is an insufficient amount of diesterformed during said addition reaction to cause gelation to occur duringsaid copolymerization.

4. A coating composition in accordance with claim 1 wherein said member(a) is present in an amount of from 55-95 percent by weight and saidaddition reaction product is present in an amount of from 5-45 percentby weight.

5. A coating composition in accordance with claim 1 which also includesa coloring pigment.

6. A method of forming the coating composition of 7 claim 1 comprisingcopolymerizing (a) 50-95 parts by weight of a member selected from thegroup conslstmg of (1) methyl methacrylate and (2) an admixture ofmethyl methacrylate and 2-30 percent by weight of a monomercopolymerizable therewith selected from acrylates of an alkanol havingone to 18 carbon atoms, methacrylates of an alkanol having two to 18carbon atoms, vinyl acetate, vinyl propionate, styrene, vinyl toluene,acrylonitrile, diesters of fumaric acid with alkanols having one to fourcarbon atoms, diesters of maleic acid with alkanols having one to fourcarbon atoms, glycidyl acrylate, glycidyl methacrylate, acrylamide, andmethacrylarnide; and (b) 5-50 parts by weight of a polymerizableaddition reaction product obtained by reacting an mB-ethylenicallyunsaturated acid and a polyepoxy in an amount of about 0.1-] 0.0 timesthe number of moles of said acid employed; and controlling the amount ofdiester formed. during said addition reaction below that point at whichgelation will occur during copolymerization by a control step whichcomprises using a chain transfer agent during said addition reactionand/or said copolymerization.

7. A method of forming the coating composition of claim 1 comprisingcopolymerizing (a) 50-95 parts by weight of a member selected from thegroup consisting of (1) methyl methacrylate and (2) an admixture ofmethyl methacrylate and 2-30 percent by weight of a monomercopolymerizable therewith selected from.

acrylates of an alkanol having one to 18 carbon atoms, methacrylates ofan alkanol having two to 18 carbon atoms, vinyl acetate, vinylpropionate, styrene, vinyl toluene, acrylonitrile, diesters of fumaricacid with alkanols having one to four carbon atoms, diesters of maleicacid with alkanols having one to four carbon atoms, glycidyl acrylate,glycidyl methacrylate, acrylamide, and methacrylamide; and (b) 5-50parts by weight of a polymerizable addition reaction product obtained byreacting an a,B-ethylenically unsaturated acid and a polyepoxy in anamount of about 0.l-l0.0 times the number of moles of said acidemployed; and controlling the amount of diester formed during saidaddition reaction below that point at which gelation will occur duringcopolymerization by a control step which comprises stopping saidaddition reaction at a time predetermined, which predetermined timeindicates that insufficient amount of diester has as yet been formed tocause gelation to occur during.

copolymerization.

Patent No. 3,697,619 Dated October 10, 1972 lnientofls) Nobuyoshi Nagataand Ryuzo Mizuguchi Itis certified that error appears in theabove-identified patent and that said Letters Patent are herebycorrected as shown below:

In the Heading:

Foreign Priority: Japanese Patent Application Numbers #6185/66 FiledJuly 16, 1966,, and

#6818/66 Filed July 19, 1966.

Assignee: Nippon Paint. Cow, Ltch, a corporation of Japan Signed andsealed this 29th day of May 1973.

(SEAL Attest:

EDWARD M.FLETCHER,JR. V w ROBERT GOTTSCHALK Attesting OffieerCommissioner of Patents FORM po'wso (169) USCOMM-DC sows-P69 v is.GOVERNMENT PRINTING OFFICE 2 I969 0-366'33l,

2. A coating composition in accordance with claim 1 wherein at least 10percent of the acid employed is allowed to react with said epoxycompound.
 3. A coating composition in accordance with claim 1 whereinsaid epoxy compound is a polyepoxide and there is an insufficient amountof diester formed during said addition reaction to cause gelation tooccur during said copolymerization.
 4. A coating composition inaccordance with claim 1 wherein said member (a) is present in an amountof from 55-95 percent by weight and said addition reaction product ispresent in an amount of from 5-45 percent by weight.
 5. A coatingcomposition in accordance with claim 1 which also includes a coloringpigment.
 6. A method of forming the coating composition of claim 1comprising copolymerizing (a) 50-95 parts by weight of a member selectedfrom the group consisting of (1) methyl methacrylate and (2) anadmixture of methyl methacrylate and 2-30 percent by weight of a monomercopolymerizable therewith selected from acrylates of an alkanol havingone to 18 carbon atoms, methacrylates of an alkanol having two to 18carbon atoms, vinyl acetate, vinyl propionate, styrene, vinyl toluene,acrylonitrile, diesters of fumaric acid with alkanols having one to fourcarbon atoms, diesters of maleic acid with alkanols having one to fourcarbon atoms, glycidyl acrylate, glycidyl methacrylate, acrylamide, andmethacrylamide; and (b) 5-50 parts by weight of a polymerizable additionreaction product obtained by reacting an Alpha , Beta -ethylenicallyunsaturated acid and a polyepoxy in an amount of about 0.1-10.0 timesthe number of moles of said acid employed; and controlling the amount ofdiester formed during said addition reaction below that point at whichgelation will occur during copolymerization by a control step whichcomprises using a chain transfer agent during said addition reactionand/or said copolymerization.
 7. A method of forming the coatingcomposition of claim 1 comprising copolymerizing (a) 50-95 parts byweight of a member selected from the group consisting of (1) methylmethacrylate and (2) an admixture of methyl methacrylate and 2-30percent by weight of a monomer copolymerizable therewith selected fromacrylates of an alkanol having one to 18 carbon atoms, methacrylates ofan alkanol having two to 18 carbon atoms, vinyl acetate, vinylpropionate, styrene, vinyl toluene, acrylonitrile, diesters of fumaricacid with alkanols having one to four carbon atoms, diesters of maleicacid with alkanols having one to four carbon atoms, glycidyl acrylate,glycidyl methacrylate, acrylamide, and methacrylamide; and (b) 5-50parts by weight of a polymerizable addition reaction product obtained byreacting an Alpha , Beta -ethylenically unsaturated acid and a polyepoxyin an amount of about 0.1-10.0 times the number of moles of said acidemployed; and controlling the amount of diester formed during saidaddition reaction below that point at which gelation will occur duringcopolymerization by a control step which comprises stopping saidaddition reaction at a time predetermined, which predetermined timeindicates that insufficient amount of diester has as yet been formed tocause gelation to occur during copolymerization.